20 research outputs found

    RECONFIGURABLE POWER AMPLIFIER WITH TUNABLE INTERSTAGE MATCHING NETWORK USING GaAs MMIC AND SURFACE-MOUNT TECHNOLOGY

    Get PDF
    As the demand of reconfigurable devices increases, the possibility of exploiting the interstage matching network in a two-stage amplifier to provide center frequency tuning capability is explored. While placement of tuning elements at the input and/or output matching network has some disadvantages, placement of tuning elements in the interstage absorbs the lossy components characteristics into useful attributes. The circuit design methodology includes graphical method to determine the bandpass topology that achieves high Q-contour on the Smith chart thus result in narrow bandwidth. T-section and π-section topologies are used to match reactive terminations provided by the first and second amplifier stages. The design methodology also includes utilization of interstage mismatch loss that decreases as increasing frequency to compensate for amplifier gain roll-off and equalize the gain at different tuning states. In prototype realization, three design configurations are discussed in this thesis: 1) a discrete design for operation between 0.1 – 0.9 GHz with the total layout area of 7.5 mm x 12.5 mm, 2) a partial monolithic design (Quasi-MMIC) for operation between 0.9 – 2.4 GHz that is 25 times smaller layout area compared to the discrete design, and 3) a conceptual design of integrated monolithic reconfigurable PA for operation between 0.9 – 2.4 GHz that is 130 times smaller layout area compared to the discrete design. One variant of the fabricated reconfigurable PA offers advantage of 4-states center frequency tuning from 1.37 GHz to 1.95 GHz with gain of 21.5 dB (+ 0.7 dB). The feasibility of interstage matching network as tuning elements in reconfigurable power amplifier has been explored. The input and output matching networks are fixed while the interstage impedances are varied using electronic switching (discrete SP4T and GaAs FET switches). The discrete design is suited for the operation at low frequency (fo < 1GHz), while monolithic implementation of the tunable interstage matching network is required for higher frequency operation due to size limitation and parasitic effects. The reconfigurable PA using MMIC tuner was designed at higher frequency to possibly cover GSM, CDMA, Bluetooth, and WiMAX frequency (0.9 – 2.4 GHz)

    RECONFIGURABLE POWER AMPLIFIER WITH TUNABLE INTERSTAGE MATCHING NETWORK USING GaAs MMIC AND SURFACE-MOUNT TECHNOLOGY

    Get PDF
    As the demand of reconfigurable devices increases, the possibility of exploiting the interstage matching network in a two-stage amplifier to provide center frequency tuning capability is explored. While placement of tuning elements at the input and/or output matching network has some disadvantages, placement of tuning elements in the interstage absorbs the lossy components characteristics into useful attributes. The circuit design methodology includes graphical method to determine the bandpass topology that achieves high Q-contour on the Smith chart thus result in narrow bandwidth. T-section and π-section topologies are used to match reactive terminations provided by the first and second amplifier stages. The design methodology also includes utilization of interstage mismatch loss that decreases as increasing frequency to compensate for amplifier gain roll-off and equalize the gain at different tuning states. In prototype realization, three design configurations are discussed in this thesis: 1) a discrete design for operation between 0.1 – 0.9 GHz with the total layout area of 7.5 mm x 12.5 mm, 2) a partial monolithic design (Quasi-MMIC) for operation between 0.9 – 2.4 GHz that is 25 times smaller layout area compared to the discrete design, and 3) a conceptual design of integrated monolithic reconfigurable PA for operation between 0.9 – 2.4 GHz that is 130 times smaller layout area compared to the discrete design. One variant of the fabricated reconfigurable PA offers advantage of 4-states center frequency tuning from 1.37 GHz to 1.95 GHz with gain of 21.5 dB (+ 0.7 dB). The feasibility of interstage matching network as tuning elements in reconfigurable power amplifier has been explored. The input and output matching networks are fixed while the interstage impedances are varied using electronic switching (discrete SP4T and GaAs FET switches). The discrete design is suited for the operation at low frequency (fo < 1GHz), while monolithic implementation of the tunable interstage matching network is required for higher frequency operation due to size limitation and parasitic effects. The reconfigurable PA using MMIC tuner was designed at higher frequency to possibly cover GSM, CDMA, Bluetooth, and WiMAX frequency (0.9 – 2.4 GHz)

    WA VELET-DCT BASED IMAGE CODER FOR VIDEO CODING APPLICATIONS

    Get PDF
    Utilization of digital video raises important concern on storage space and transmission purpose. A video codec that compresses digital video signal has become an essential component in video application. The interest of this project is to integrate a wavelet-based compression and at the same time providing a backward compatibility to the existing architecture of MPEG-2 standard. Wavelet-DCT is an algorithm that utilizes Discrete Wavelet Transform (DWT) to compute Discrete Cosine Transform (DCT) coefficients. The algorithm allows truncation of intermediate coefficient through DWT. This process is also known as thresholding. The Wavelet-DCT algorithm is integrated into a simulation of intra-frame coder in compliance with MPEG-2 standard. To enhance the system performance, threshold level selection is done via histogram energy analysis and selection of best wavelet type through statistical study. The simulation was developed using SIMULINK and MATLAB. WaveletDCT based intra-frame coder was simulated by employing two different approaches. Different types of multimedia source (image and video) were tested on the simulation. The result from both approaches for images shows marginal improvement at higher compression ratio. On the other hand, when it was tested on video, which consists of different types of images, both approaches does not show a reasonable improvement at various level of compression ratio. The argument on why wavelet-DCT based intra-frame coder does not perform better arises from the objective's restriction that attempts to cater the backward compatibility. Some recommended areas to be delved for future work on video compression are distributed video coding, ridgelet transform and dual-tree complex wavelet transform

    Peranan Desain Grafis di PT Dnartworks Komunikasi Visual

    Get PDF
    Di jaman sekarang adanya desain grafis dan branding dapat membuat produk atau jasa dikenal dan dibedakan dari kompetitor lain. Dengan penyataan ini membuat penulis memilih untuk melakukan praktek magang memperdalam wawasan dan pengalaman di bagian desain grafis juga branding di Piktora studio. Piktora studio merupakan agensi graphic design studio yang berfokus dalam mengerjakan desain grafis, branding, dan website. Praktek magang ini juga sebagai salah satu syarat kelulusan dari Universitas Multimedia Nusantara. Kerja di dunia nyata tentu sangat berbeda dengan dunia perkuliahan itulah yang penulis dapatkan dalam menjalani kegiatan magang selama tiga bulan di Piktora studio. Dalam proses kerja magang penulis mendapatkan banyak wawasan baru dan pengalaman tak berharga bagi penulis. Selama melaksanakan proses magang, penulis ditempatkan sebagai Graphic Design Intern. Melalui proses kerja magang, banyak mengajarkan penulis akan alur koordinasi kerja mendesain, bersikap profesional saat menghadapi klien, berani memberikan pendapat saat berdiskusi tim, bekerja dibawah tekanan, dan pengaturan waktu dalam mendesain hingga hasil akhir

    Outdoor Temperature Influences Cold Induced Thermogenesis in Humans

    Get PDF
    Objective: Energy expenditure (EE) increases in response to cold exposure, which is called cold induced thermogenesis (CIT). Brown adipose tissue (BAT) has been shown to contribute significantly to CIT in human adults. BAT activity and CIT are acutely influenced by ambient temperature. In the present study, we investigated the long-term effect of seasonal temperature variation on human CIT.Materials and Methods: We measured CIT in 56 healthy volunteers by indirect calorimetry. CIT was determined as difference between EE during warm conditions (EEwarm) and after a defined cold stimulus (EEcold). We recorded skin temperatures at eleven anatomically predefined locations, including the supraclavicular region, which is adjacent to the main human BAT depot. We analyzed the relation of EE, CIT and skin temperatures to the daily minimum, maximum and mean outdoor temperature averaged over 7 or 30 days, respectively, prior to the corresponding study visit by linear regression.Results: We observed a significant inverse correlation between outdoor temperatures and EEcold and CIT, respectively, while EEwarm was not influenced. The daily maximum temperature averaged over 7 days correlated best with EEcold (R2 = 0.123, p = 0.008) and CIT (R2 = 0.200, p = 0.0005). The mean skin temperatures before and after cold exposure were not related to outdoor temperatures. However, the difference between supraclavicular and parasternal skin temperature after cold exposure was inversely related to the average maximum temperature during the preceding 7 days (R2 = 0.07575, p = 0.0221).Conclusion: CIT is significantly related to outdoor temperatures indicating dynamic adaption of thermogenesis and BAT activity to environmental stimuli in adult humans.Clinical Trial Registration:www.ClinicalTrials.gov, Identifier NCT02682706

    The impact of surgical delay on resectability of colorectal cancer: An international prospective cohort study

    Get PDF
    AIM: The SARS-CoV-2 pandemic has provided a unique opportunity to explore the impact of surgical delays on cancer resectability. This study aimed to compare resectability for colorectal cancer patients undergoing delayed versus non-delayed surgery. METHODS: This was an international prospective cohort study of consecutive colorectal cancer patients with a decision for curative surgery (January-April 2020). Surgical delay was defined as an operation taking place more than 4 weeks after treatment decision, in a patient who did not receive neoadjuvant therapy. A subgroup analysis explored the effects of delay in elective patients only. The impact of longer delays was explored in a sensitivity analysis. The primary outcome was complete resection, defined as curative resection with an R0 margin. RESULTS: Overall, 5453 patients from 304 hospitals in 47 countries were included, of whom 6.6% (358/5453) did not receive their planned operation. Of the 4304 operated patients without neoadjuvant therapy, 40.5% (1744/4304) were delayed beyond 4 weeks. Delayed patients were more likely to be older, men, more comorbid, have higher body mass index and have rectal cancer and early stage disease. Delayed patients had higher unadjusted rates of complete resection (93.7% vs. 91.9%, P = 0.032) and lower rates of emergency surgery (4.5% vs. 22.5%, P < 0.001). After adjustment, delay was not associated with a lower rate of complete resection (OR 1.18, 95% CI 0.90-1.55, P = 0.224), which was consistent in elective patients only (OR 0.94, 95% CI 0.69-1.27, P = 0.672). Longer delays were not associated with poorer outcomes. CONCLUSION: One in 15 colorectal cancer patients did not receive their planned operation during the first wave of COVID-19. Surgical delay did not appear to compromise resectability, raising the hypothesis that any reduction in long-term survival attributable to delays is likely to be due to micro-metastatic disease

    Outcomes from elective colorectal cancer surgery during the SARS-CoV-2 pandemic

    Get PDF
    This study aimed to describe the change in surgical practice and the impact of SARS-CoV-2 on mortality after surgical resection of colorectal cancer during the initial phases of the SARS-CoV-2 pandemic

    Elective cancer surgery in COVID-19-free surgical pathways during the SARS-CoV-2 pandemic: An international, multicenter, comparative cohort study

    Get PDF
    PURPOSE As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19–free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19–free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19–free surgical pathways. Patients who underwent surgery within COVID-19–free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19–free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score–matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19–free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION Within available resources, dedicated COVID-19–free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

    Elective Cancer Surgery in COVID-19-Free Surgical Pathways During the SARS-CoV-2 Pandemic: An International, Multicenter, Comparative Cohort Study.

    Get PDF
    PURPOSE: As cancer surgery restarts after the first COVID-19 wave, health care providers urgently require data to determine where elective surgery is best performed. This study aimed to determine whether COVID-19-free surgical pathways were associated with lower postoperative pulmonary complication rates compared with hospitals with no defined pathway. PATIENTS AND METHODS: This international, multicenter cohort study included patients who underwent elective surgery for 10 solid cancer types without preoperative suspicion of SARS-CoV-2. Participating hospitals included patients from local emergence of SARS-CoV-2 until April 19, 2020. At the time of surgery, hospitals were defined as having a COVID-19-free surgical pathway (complete segregation of the operating theater, critical care, and inpatient ward areas) or no defined pathway (incomplete or no segregation, areas shared with patients with COVID-19). The primary outcome was 30-day postoperative pulmonary complications (pneumonia, acute respiratory distress syndrome, unexpected ventilation). RESULTS: Of 9,171 patients from 447 hospitals in 55 countries, 2,481 were operated on in COVID-19-free surgical pathways. Patients who underwent surgery within COVID-19-free surgical pathways were younger with fewer comorbidities than those in hospitals with no defined pathway but with similar proportions of major surgery. After adjustment, pulmonary complication rates were lower with COVID-19-free surgical pathways (2.2% v 4.9%; adjusted odds ratio [aOR], 0.62; 95% CI, 0.44 to 0.86). This was consistent in sensitivity analyses for low-risk patients (American Society of Anesthesiologists grade 1/2), propensity score-matched models, and patients with negative SARS-CoV-2 preoperative tests. The postoperative SARS-CoV-2 infection rate was also lower in COVID-19-free surgical pathways (2.1% v 3.6%; aOR, 0.53; 95% CI, 0.36 to 0.76). CONCLUSION: Within available resources, dedicated COVID-19-free surgical pathways should be established to provide safe elective cancer surgery during current and before future SARS-CoV-2 outbreaks

    Perancangan Promosi Restoran Kaca Mata

    Get PDF
    Restoran Kaca Mata merupakan restoran chinese food yang telah berdiri sejak 1956. Restoran Kaca Mata yang memiliki spesialis makanan nasi campur dan chasio garing madu ini awalnya berasal dari Medan dan memulai lembaran baru di Jakarta di tahun 1988. Salah satu faktor yang menghambat peningkatan penjualan adalah kurangnya awareness masyarakat zaman sekarang terhadap restoran Kaca Mata juga lemahnya restoran Kaca Mata dibagian promosi dibanding kompetitor lainnya. Maka dari itulah dibutuhkannya promosi untuk meningkatkan awareness masyarakat terhadap restoran Kaca Mata menggunakan media zaman sekarang. Dalam perancangan tugas akhir ini, penulis menggunakan metode penelitian kuantitatif beserta kualitatif berupa kuesioner, wawancara, observasi lapangan, dan studi existing. Penulis berharap dengan adanya perancangan promosi yang tepat, dapat meningkatkan penjualan mencapai target yang diinginkan juga meningkatnya awareness yang ada terhadap restoran Kacamata. Laporan ini berisi penjelasan latar belakang masalah dari restoran Kaca Mata, metode penelitian yang telah dilakukan penulis, hingga proses perancangan yang dilalui penulis untuk menciptakan karya promosi restoran Kaca Mata
    corecore